Flexible display apparatus and method of manufacturing the same

ABSTRACT

A flexible display apparatus including: a first film including a first surface and a second surface that are opposite each other, and a first groove formed in the first surface, the first film having a first rigidity; a third film on the second surface of the first film; a fourth film facing the third film; an emission display unit between and encapsulated by the third film and the fourth film; and a second film on the fourth film and facing the first film, the second film having a second rigidity that is less than the first rigidity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/057,040, filed on Feb. 29, 2016, now U.S. Pat. No. 10,128,460, issuedon Nov. 13, 2018, which is a continuation of U.S. patent applicationSer. No. 14/970,222, filed on Dec. 15, 2015, now U.S. Pat. No.9,698,375, issued on Jul. 4, 2017, which is a continuation of U.S.patent application Ser. No. 13/472,374, filed on May 15, 2012, now U.S.Pat. No. 9,274,559, issued on Mar. 1, 2016, which claims priority to andthe benefit of Korean Patent Application No. 10-2011-0144982, filed onDec. 28, 2011 in the Korean Intellectual Property Office, the entirecontent of each of which is incorporated herein by reference. U.S.patent application Ser. No. 15/057,040 is also a continuation of U.S.patent application Ser. No. 13/472,374, filed on May 15, 2012, now U.S.Pat. No. 9,274,559, issued on Mar. 1, 2016, which claims priority to andthe benefit of Korean Patent Application No. 10-2011-0144982, filed onDec. 28, 2011 in the Korean Intellectual Property Office.

BACKGROUND 1. Field

Aspects of embodiments of the present invention relate to a flexibledisplay apparatus and a method of manufacturing the same.

2. Description of the Related Art

A display apparatus is an apparatus that displays an image signal. Thedisplay apparatus is any apparatus that displays an image signalreceived from an external source and includes televisions, computermonitors, personal digital assistants (PDAs), smart devices that arerecently in great demand, or the like.

For the display apparatus, a high-definition flat display moduleincluding an organic light-emitting display panel, a liquid crystaldisplay panel, a plasma display panel, an electrophoretic display panel,or the like is used.

Recently, a flexible display apparatus that is lightweight, slim, andportable, and that may be bent or folded is being developed. Theflexible display apparatus may be embodied by using a flexible substratesuch as a plastic, instead of using a glass substrate.

However, a shape of the flexible substrate is not fixed but is flexible,such that it is difficult to precisely form various types of devices andwirings included in the display apparatus.

Also, since a stress exceeding a breaking strength due to excessivebending or a repetitive stress due to repetitive bending may be appliedto the display apparatus, a lifetime of the display apparatus isdecreased, and the devices and wirings are damaged.

SUMMARY

According to an aspect of embodiments of the present invention, aflexible display apparatus has a decreased stress occurring in a bendingportion when the flexible display apparatus is folded or bent.

According to one embodiment of the present invention, a flexible displayapparatus includes: a first film including a first surface and a secondsurface that are opposite each other, and a first groove formed in thefirst surface, the first film having a first rigidity; a third film onthe second surface of the first film; a fourth film facing the thirdfilm; an emission display unit between and encapsulated by the thirdfilm and the fourth film; and a second film on the fourth film andfacing the first film, the second film having a second rigidity that isless than the first rigidity.

The flexible display apparatus may include a neutral portion in which atensile stress and a compressive stress are not incurred by a force whenthe force capable of bending the flexible display apparatus is appliedto the flexible display apparatus, and the emission display unit may bepositioned at the neutral portion.

The flexible display apparatus may further include a bending portionconfigured to be bent, and the first groove may be positioned at thebending portion.

The first groove may include a plurality of grooves.

The first groove may have a V-shape.

A depth h₁ of the first groove may satisfy an equation:0<h ₁ ≤t ₁,

where t₁ is a thickness of the first film.

The first film may be divided by the first groove into a first regionand a second region, and a portion of the third film may be exposed at aregion corresponding to the first groove.

The flexible display apparatus may further include an elastic member inthe first groove.

The second film may include a third surface adjacent to the fourth film,and a fourth surface opposite the third surface and having a secondgroove formed therein.

The third film may have flexibility, and the fourth film may be formedas a thin film including a multi-layered inorganic film, or an inorganicfilm and an organic film.

According to another embodiment of the present invention, a method ofmanufacturing a flexible display apparatus includes: forming a thirdfilm on a supporting substrate; forming an emission display unit on thethird film; forming a fourth film on the emission display unit; forminga second film having a second rigidity on the fourth film; separatingthe supporting substrate from the third film; and forming a first filmon a surface of the third film opposite to another surface of the thirdfilm on which the emission display unit is formed, wherein the firstfilm has a first rigidity greater than the second rigidity and includesa second surface adjacent to the third film, and a first surface that isopposite to the second surface and has a first groove.

The flexible display apparatus may include a neutral portion in which atensile stress and a compressive stress are not incurred by a force whenthe force capable of bending the flexible display apparatus is appliedto the flexible display apparatus, and the emission display unit may bepositioned at the neutral portion.

Forming the first film may include forming the first film having thefirst groove such that the first groove is positioned at a bendingportion formed in the flexible display apparatus to allow the flexibledisplay apparatus to be bent.

The first groove may include a plurality of grooves.

The first groove may have a V-shape.

A depth h₁ of the first groove may satisfy an equation:0<h ₁ ≤t ₁,

where t₁ is a thickness of the first film.

The first film may be divided by the first groove into a first regionand a second region, and a portion of the third film may be exposed at aregion corresponding to the first groove.

The method may further include forming an elastic member in the firstgroove.

The second film may include a third surface adjacent to the fourth film,and a fourth surface opposite the third surface and having a secondgroove formed therein.

The third film may have flexibility, and the fourth film may be formedas a thin film including a multi-layered inorganic film, or an inorganicfilm and an organic film.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and aspects of the present invention willbecome more apparent by describing in further detail some exemplaryembodiments thereof with reference to the attached drawings in which:

FIG. 1 is a cross-sectional view of a flexible display apparatusaccording to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a pixel region of a display panelunit of the flexible display apparatus of FIG. 1;

FIGS. 3 and 4 are perspective views illustrating bent states of theflexible display apparatus of FIG. 1;

FIGS. 5 through 8 are cross-sectional views that sequentially illustratea method of manufacturing the flexible display apparatus of FIG. 1,according to an embodiment of the present invention;

FIG. 9 is a cross-sectional view of a flexible display apparatusaccording to another embodiment of the present invention;

FIGS. 10 and 11 are perspective views illustrating bent states of theflexible display apparatus of FIG. 9;

FIG. 12 is a cross-sectional view of a flexible display apparatusaccording to another embodiment of the present invention;

FIGS. 13 and 14 are perspective views illustrating bent states of theflexible display apparatus of FIG. 12;

FIG. 15 is a cross-sectional view of a flexible display apparatusaccording to another embodiment of the present invention; and

FIG. 16 is a cross-sectional view of a flexible display apparatusaccording to another embodiment of the present invention.

DETAILED DESCRIPTION

Some exemplary embodiments of the present invention are described morefully hereinafter with reference to the accompanying drawings; however,embodiments of the present invention may be embodied in different formsand should not be construed as limited to the exemplary embodimentsillustrated and set forth herein. Rather, these exemplary embodimentsare provided by way of example for understanding of the invention and toconvey the scope of the invention to those skilled in the art. As thoseskilled in the art would realize, the described embodiments may bemodified in various ways, all without departing from the spirit or scopeof the present invention.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

FIG. 1 is a cross-sectional view of a flexible display apparatus 1according to an embodiment of the present invention. FIG. 2 is across-sectional view of a pixel region of a display panel unit 200 ofthe flexible display apparatus 1 of FIG. 1.

Referring to FIG. 1, the flexible display apparatus 1, in oneembodiment, includes a first film 100 having a first surface 101 and asecond surface 102 that are opposite each other, having a first groove110 formed in the first surface 101, and having a first rigidity. Theflexible display apparatus 1, in one embodiment, further includes thedisplay panel unit 200 including a third film 210 disposed on the secondsurface 102 of the first film 100, a fourth film 230 disposed to facethe third film 210, and an emission display unit 220 interposed betweenthe third film 210 and the fourth film 230, and encapsulated by thethird film 210 and the fourth film 230. The flexible display apparatus1, in one embodiment, further includes a second film 300 disposed on thefourth film 230 so as to face the first film 100, and having a secondrigidity that is less than the first rigidity of the first film 100.

The first film 100 and the second film 300 may be formed of a plastic,and the second film 300 has flexibility. The first film 100 may beformed of a material having a rigidity greater than a rigidity of thesecond film 300. Although the first film 100 may have flexibility, thefirst film 100, in one embodiment, has a rigidity greater than therigidity of the second film 300.

By forming the first film 100 of a material having a relatively greaterrigidity, durability of the flexible display apparatus 1 may beimproved, and damage to the display panel unit 200 may be prevented orsubstantially prevented.

In one embodiment, the first film 100 and the second film 300 are formedof a plastic, but a material of the first film 100 and the second film300 is not limited thereto, and, in other embodiments of the presentinvention, the first film 100 and the second film 300 may be formed ofvarious other materials.

The flexible display apparatus 1 may be bent in such a manner that thefirst film 100 having relatively greater rigidity, i.e. havingrelatively less flexibility, may be disposed at an inner side, and atensile stress may be applied to the second film 300, and a compressivestress may be applied to the first film 100.

The flexible display apparatus 1 may be repetitively bent due to anexternal force, and when a stress greater than or equal to a breakingstrength is applied to the display panel unit 200, the display panelunit 200 may be damaged. In order to decrease a stress occurring in theflexible display apparatus 1, the first film 100 has the first groove110 that is formed in the first surface 101.

In order to avoid or decrease the compressive stress applied to thefirst film 100, the first groove 110 may be positioned at a bendingportion (i.e. a portion B in each of FIGS. 3 and 4) of the flexibledisplay apparatus 1, i.e. at a region having the greatest stress.

The display panel unit 200 is disposed between the first film 100 andthe second film 300.

Referring to FIG. 2, in one embodiment, the display panel unit 200 mayinclude the third film 210 having flexibility and disposed on the secondsurface 102 of the first film 100, the emission display unit 220disposed on the third film 210, and the fourth film 230 that is disposedon the emission display unit 220 so as to face the third film 210 andthat, together with the third film 210, encapsulates the emissiondisplay unit 220. In one embodiment, a barrier layer 240 and adevice/wiring layer 250 may be further disposed between the third film210 and the emission display unit 220.

The third film 210, in one embodiment, may be formed of a plasticmaterial including polyethylene ether phthalate, polyethylenenaphthalate (PEN), polycarbonate, polyetherimide, polyether sulfone,polyimide, or the like. However, one or more embodiments of the presentinvention are not limited thereto, and the third film 210 may be formedof various other flexible materials.

The barrier layer 240, in one embodiment, may be disposed on the thirdfilm 210. The third film 210 prevents or substantially prevents foreignsubstances such as moisture or oxygen from passing through the thirdfilm 210 and then penetrating into a thin film transistor (TFT) and/orthe emission display unit 220.

The device/wiring layer 250, in one embodiment, may be disposed on thebarrier layer 240 and may include a driving TFT for driving the emissiondisplay unit 220 (i.e. an organic light-emitting diode (OLED)), aswitching TFT (not shown), a capacitor, and wirings (not shown) that areconnected to the TFT or the capacitor.

The driving TFT includes an active layer 251, a gate electrode 253, andsource and drain electrodes 255 a and 255 b.

The emission display unit 220, in one embodiment, is disposed on thedevice/wiring layer 250. The emission display unit 220 includes a pixelelectrode 221, an organic emission layer 222 disposed on the pixelelectrode 221, and an opposite electrode 223 formed on the organicemission layer 222.

In one embodiment, the pixel electrode 221 is an anode, and the oppositeelectrode 223 is a cathode. However, one or more embodiments of thepresent invention are not limited thereto and thus, according to amethod of driving the flexible display apparatus 1, the pixel electrode221 may be a cathode, and the opposite electrode 223 may be an anode.Holes and electrons that are output from the pixel electrode 221 and theopposite electrode 223, respectively, are injected into the organicemission layer 222. The injected holes and electrons form excitons, andwhen the excitons turn to an excited state from a ground state, light isemitted.

The pixel electrode 221 is electrically connected to the driving TFTformed in the device/wiring layer 250.

In one embodiment, the emission display unit 220 is disposed on thedevice/wiring layer 250 in which the driving TFT is formed. However, oneor more embodiments of the present invention are not limited thereto,and thus the structure may be variously changed to a structure in whichthe pixel electrode 221 of the emission display unit 220 is formed onthe same layer as the active layer 251 of the TFT, a structure in whichthe pixel electrode 221 is formed on the same layer as the gateelectrode 253, a structure in which the pixel electrode 221 is formed onthe same layer as the source and the drain electrodes 255 a and 255 b,or the like.

Also, in the driving TFT according to one embodiment, the gate electrode253 is disposed on the active layer 251. However, one or moreembodiments of the present invention are not limited thereto, and thusthe gate electrode 253 may be disposed below the active layer 251.

The pixel electrode 221 included in the emission display unit 220 may bea reflective electrode, and may include a reflective layer formed of Ag,Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound of any of these, and atransparent or translucent electrode layer may be formed on thereflective layer.

The transparent or translucent electrode layer may include at least onematerial selected from the group consisting of indium tin oxide (ITO),indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In₂O₃), indiumgallium oxide (IGO), and aluminum zinc oxide (AZO).

The opposite electrode 223 that is disposed to face the pixel electrode221 may be a transparent or translucent electrode, and may be formed ofa metal thin film having a low work function and including a materialLi, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, or a compound of any of these. Also,an auxiliary electrode layer or a bus electrode may be further formed onthe metal thin film, wherein the auxiliary electrode layer or the buselectrode may be formed of a material including ITO, IZO, ZnO or In₂O₃for the transparent or translucent electrode.

Thus, the opposite electrode 223 may transmit light emitted from theorganic emission layer 222.

The organic emission layer 222 is disposed between the pixel electrode221 and the opposite electrode 223, and the organic emission layer 222may be a small-molecule organic layer or a polymer organic layer.

In addition to the organic emission layer 222, intermediate layersincluding a hole transport layer (HTL), a hole injection layer (HIL), anelectron transport layer (ETL), an electron injection layer (EIL), orthe like may be selectively disposed between the pixel electrode 221 andthe opposite electrode 223.

The flexible display apparatus 1 may be a top emission type flexibledisplay apparatus in which light emitted from the organic emission layer222 is directly emitted or is reflected by the pixel electrode 221formed as the reflective electrode, and then travels to the oppositeelectrode 223.

However, a type of the flexible display apparatus 1 is not limited tothe top emission type flexible display apparatus, and thus may be abottom emission type flexible display apparatus in which light generatedin the organic emission layer 222 is emitted to the third film 210. Inthis case, the pixel electrode 221 may be formed as a transparent ortranslucent electrode, and the opposite electrode 223 may be formed as areflective electrode.

In one embodiment, the flexible display apparatus 1 may be adual-emission type flexible display apparatus in which light is emittedto a top surface and a bottom surface.

The fourth film 230 may be disposed on the opposite electrode 223. Thefourth film 230 may be formed as a multi-layered inorganic film, or athin film including an inorganic film and an organic film. The fourthfilm 230 may function to prevent or substantially prevent penetration ofexternal moisture and oxygen into the emission display unit 220.

The flexible display apparatus 1 according to one embodiment includesthe display panel unit 200 including the third film 210 havingflexibility, and the fourth film 230 formed as a thin film, the firstfilm 100 having the first groove 110, and the second film 300 havingflexibility, such that the flexible display apparatus 1 may haveflexibility and slimness.

When an external force is applied to the flexible display apparatus 1 soas to bend the flexible display apparatus 1, a tensile stress is appliedto the second film 300 disposed at an outer side of the bending portionB, and a compressive stress is applied to the first film 100 disposed atan inner side of the bending portion B.

In one embodiment, a neutral portion in which neither the tensile stressnor the compressive stress occurs exists between the first film 100 andthe second film 300. When the emission display unit 220 is disposed inthe neutral portion, a stress applied to the emission display unit 220is minimized or reduced such that damage due to bending may be preventedor substantially prevented.

In one embodiment, in order to avoid or decrease the compressive stressapplied to the first film 100, the first groove 110 is formed in thefirst surface 101 of the first film 100. The first groove 110 may bepositioned at the bending portion B, i.e. the region to which thegreatest stress is applied when the flexible display apparatus 1 isbent.

In one embodiment, the first groove 110 may have a V-shape. In thisregard, a width L₁ and a depth h₁ of the V-shape may have various valuesaccording to a bending amount.

In one embodiment, the depth h₁ may satisfy the equation of 0<h₁≤t₁.Here, t₁ is a thickness of the first film 100.

In one embodiment, the first groove 110 is formed as a single groove.However, one or more embodiments of the present invention are notlimited thereto, and thus a plurality of the first grooves 110 may beformed.

In one embodiment, the second film 300 may have a third surface 301adjacent to the display panel unit 200, and a fourth surface 302opposite to the third surface 301.

In the flexible display apparatus 1 according to one embodiment, thefirst film 100 having a relatively great rigidity is disposed below thedisplay panel unit 200, i.e. is disposed toward the third film 210, andthe second film 300 having great flexibility is disposed on the displaypanel unit 200, i.e. is disposed toward the fourth film 230. However, inanother embodiment, disposition of the first film 100 and the secondfilm 300 may be reversed.

In one embodiment, the first film 100 and/or the second film 300disposed in an emission direction may include a polarizing film.

Also, while the emission display unit 220 of the display panel unit 200included in the flexible display apparatus 1 includes the organicemission layer 222, one or more embodiments of the present invention arenot limited thereto, and thus the display panel unit 200 may include aliquid crystal display (LCD) device, a plasma display device, anelectrophoretic display device, or the like.

FIGS. 3 and 4 are perspective views illustrating bent states of theflexible display apparatus 1 of FIG. 1.

Referring to FIG. 3, the first film 100 includes a first region 120 anda second region 130, and the flexible display apparatus 1 includes thebending portion B at which the first region 120 and the second region130 of the first film 100 are bent in an approximately verticaldirection.

The first groove 110 is formed at a region of the first film 100 whichcorresponds to the bending portion B, and, in one embodiment, a width L₁of the first groove 110 may be twice as great as the thickness t₁ of thefirst film 100, i.e. L₁=2×t₁, and the depth h₁ may be the same as thethickness t₁ of the first film 100, i.e. h₁=t₁.

As a result of the aforementioned structure, although the flexibledisplay apparatus 1 may be bent as shown in FIG. 3, a compressive stressis not applied to the first film 100.

Referring to FIG. 4, the first film 100 includes the first region 120and the second region 130, and the flexible display apparatus 1 includesthe bending portion B at which the first region 120 and the secondregion 130 of the first film 100 are bent in an approximately horizontaldirection.

In one embodiment, the width L₁ of the first groove 110 formed in thefirst film 100 may be at least two times greater than the thickness t₁of the first film 100, and the depth h₁ may be the same as the thicknesst₁ of the first film 100.

Here, a certain compressive stress may be applied to the first film 100according to the width L₁. However, compared to a case without the firstgroove 110, an amount of the compressive stress is significantlydecreased.

FIGS. 5 through 8 are cross-sectional views that sequentially illustratea method of manufacturing the flexible display apparatus 1 of FIG. 1,according to an embodiment of the present invention.

Referring to FIG. 5, the display panel unit 200 including the third film210 having flexibility, the emission display unit 220, and the fourthfilm 230, together with the third film 230, encapsulating the emissiondisplay unit 220 is formed on a supporting substrate 400.

The supporting substrate 400 may be formed of glass. Since the thirdfilm 210 having flexibility and formed of a plastic may be deformed dueto heat, it is difficult to precisely form the TFT or the emissiondisplay unit 220 on the third film 210.

Thus, after the third film 210 is deposited on the supporting substrate400, a subsequent process may be performed.

The emission display unit 220, in one embodiment, is formed bysequentially forming the pixel electrode 221 (refer to FIG. 2), theorganic emission layer 222 (refer to FIG. 2), and the opposite electrode223 (refer to FIG. 2) on the third film 210, and then the fourth film230 is formed to cover the emission display unit 220.

The fourth film 230 may be formed as a multi-layered inorganic film, ora thin film including an inorganic film and an organic film.

Referring to FIG. 6, the second film 300 having the second rigidity isbonded on the fourth film 230.

The second film 300 may be formed as a flexible film such as a plastic,and an adhesion layer (not shown) to bond the fourth film 230 and thesecond film 300 may be disposed between the fourth film 230 and thesecond film 300.

Referring to FIG. 7, the supporting substrate 400 is separated from thethird film 210.

The supporting substrate 400 may be separated from the third film 210 bya general method such as etching.

Referring to FIG. 8, the first film 100 that has the first rigiditygreater than the second rigidity and that includes the second surface102 adjacent to the third film 210, and the first surface 101 oppositeto the second surface 102 and having the first groove 110 is bonded on asurface opposite to a surface of the third film 210 on which theemission display unit 220 is disposed.

Here, an adhesion layer 205 to bond the first film 100 and the thirdfilm 210 may be disposed between the first film 100 and the third film210.

FIG. 9 is a cross-sectional view of a flexible display apparatus 2according to another embodiment of the present invention.

Referring to FIG. 9, the flexible display apparatus 2 according to oneembodiment is the same as the flexible display apparatus 1 of FIG. 1,except for a configuration of a first film 100′.

The first film 100′ has a first groove 110′, and a first region 120′ anda second region 130′ that are separated by the first groove 110′. In oneembodiment, a portion of the third film 210 is exposed at a regioncorresponding to the first groove 110′.

A width L₂ and a depth h₂ of the first groove 110′ included in the firstfilm 100′ may have various values according to a bending level.

FIGS. 10 and 11 are perspective views illustrating bent states of theflexible display apparatus 2 of FIG. 9.

Referring to FIG. 10, the first film 100′ is divided into the firstregion 120′ and the second region 130′, and the flexible displayapparatus 2 includes a bending portion B′ at which the first region 120′and the second region 130′ of the first film 100′ are bent in anapproximately vertical direction.

In one embodiment, the first groove 110′ of the first film 100′ isdisposed at the bending portion B′, and the bending portion B′ has anempty space surrounded by the first region 120′ and the second region130′.

In one embodiment, the width L₂ of the first groove 110′ included in thefirst film 100′ may be twice as great as a thickness t₂ of the firstfilm 100′, i.e. L₂=2×t₂, and the depth h₂ may be the same as thethickness t₂ of the first film 100′, i.e. h₂=t₂.

Due to the aforementioned structure, although the flexible displayapparatus 2 may be bent as shown in FIG. 10, a compressive stress is notapplied to the first film 100′.

Referring to FIG. 11, the first film 100′ is divided into the firstregion 120′ and the second region 130′, and the flexible displayapparatus 2 includes the bending portion B′ at which the first region120′ and the second region 130′ of the first film 100′ are bent in anapproximately horizontal direction.

In one embodiment, the first groove 110′ of the first film 100′ isdisposed at the bending portion B′, and the bending portion B′ has anempty space surrounded by the first region 120′ and the second region130′.

Here, a certain compressive stress may be applied to the first film 100′according to values of the width L₂ and the depth h₂ of the first groove110′. However, compared to a case without the first groove 110′, a levelof the compressive stress is significantly decreased.

FIG. 12 is a cross-sectional view of a flexible display apparatus 3according to another embodiment of the present invention.

Referring to FIG. 12, the flexible display apparatus 3 according to oneembodiment is the same as the flexible display apparatus 2 of FIG. 12,except that the flexible display apparatus 3 has an elastic member 500that is disposed to fill the first groove 110′ included in the firstfilm 100′.

The elastic member 500, in one embodiment, is formed of a materialhaving greater flexibility than that of the first film 100′. When theflexible display apparatus 3 is bent, the first groove 110′ may beformed at a bending portion (refer to a portion B′ in each of FIGS. 13and 14), i.e. in a region having the greatest compressive stress, andthe elastic member 500 may fill the first groove 110′ such that acompressive stress is decreased.

Since the elastic member 500 fills the first groove 110′, the displaypanel unit 200 is not externally exposed.

FIGS. 13 and 14 are perspective views illustrating bent states of theflexible display apparatus 3 of FIG. 12.

Referring to FIG. 13, the first film 100′ is divided into the firstregion 120′ and the second region 130′, and the flexible displayapparatus 3 includes the bending portion B′ at which the first region120′ and the second region 130′ of the first film 100′ are bent in anapproximately vertical direction.

Here, the first groove 110′ of the first film 100′ is disposed at thebending portion B′, and the elastic member 500 is disposed at a regionsurrounded by the first region 120′ and the second region 130′.

Referring to FIG. 14, the first film 100′ is divided into the firstregion 120′ and the second region 130′, and the flexible displayapparatus 3 includes the bending portion B′ at which the first region120′ and the second region 130′ of the first film 100′ are bent in anapproximately horizontal direction.

Here, the first groove 110′ of the first film 100′ is disposed at thebending portion B′, and the elastic member 500 is disposed at a regionsurrounded by the first region 120′ and the second region 130′.

In the flexible display apparatus 3 according to one embodiment, theelastic member 500 having relatively great flexibility is disposed inthe first groove 110′ of the first film 100′ such that, although theflexible display apparatus 3 may be bent as shown in FIGS. 13 and 14, astress applied to the first film 100′ is decreased.

FIG. 15 is a cross-sectional view of a flexible display apparatus 4according to another embodiment of the present invention.

Referring to FIG. 15, the flexible display apparatus 4 according to oneembodiment is the same as the flexible display apparatus 1 of FIG. 1,except that the flexible display apparatus 4 has a structure in whichtwo first grooves 110″ are disposed in a first film 100″.

In one embodiment, the first grooves 110″ have a constant width L₃ and aconstant height h₃. Here, the height h₃ may be less than a thickness t₃of the first film 100″, but is not limited thereto.

FIG. 16 is a cross-sectional view of a flexible display apparatus 5according to another embodiment of the present invention.

Referring to FIG. 16, the flexible display apparatus 5 according to oneembodiment is the same as the flexible display apparatus 1 of FIG. 1,except that the flexible display apparatus 5 has a structure in which asecond film 300′ has the third surface 301 adjacent to the display panelunit 200, and the fourth surface 302 opposite to the third surface 301,and includes a second groove 310 in the fourth surface 302.

In one embodiment, the first groove 110 and the second groove 310 maycorrespond to each other, but are not limited thereto. Theaforementioned description with respect to the first groove 110 may beequally applied to the second groove 310, and thus further descriptionof the second groove 310 is omitted here.

In the flexible display apparatus according to one or more embodimentsof the present invention, a groove is disposed in a bending portion ofthe flexible display apparatus, such that a stress due to a folding orbending operation may be decreased.

Also, by bonding a separate film on the display panel unit, durabilityof the flexible display apparatus may be improved.

Also, by disposing the emission display unit in a neutral portion,damage of a device formed in the emission display unit, which is causeddue to a folding or bending operation, may be prevented or substantiallyprevented.

While the present invention has been particularly shown and describedwith reference to some exemplary embodiments thereof, it will beunderstood by those of ordinary skill in the art that various changes inform and details may be made therein without departing from the spiritand scope of the present invention as defined by the following claims.

What is claimed is:
 1. A flexible display apparatus comprising: a firstfilm including a first region and a second region separated from thefirst region by a first opening or groove of the first film, the firstopening or groove being disposed in the first film; a third film overthe first film; a fourth film over the third film; an emission displayunit between the third film and the fourth film; and an adhesion layerbetween the first film and the third film; wherein a width of the firstopening or groove of the first film is at least two times greater than athickness of the first film, and a surface of the adhesion layer betweenthe third film and the first film is exposed by the first opening orgroove.
 2. The flexible display apparatus of claim 1, wherein the thirdfilm comprises a plastic material.
 3. The flexible display apparatus ofclaim 1, wherein the fourth film comprises a multi-layer.
 4. Theflexible display apparatus of claim 3, wherein the multi-layer comprisesat least one inorganic film.
 5. The flexible display apparatus of claim1, wherein the fourth film is configured to encapsulate the emissiondisplay unit.
 6. The flexible display apparatus of claim 1, furthercomprising a barrier film between the third film and the emissiondisplay unit.
 7. The flexible display apparatus of claim 1, furthercomprising a device/wiring layer between the third film and the emissiondisplay unit.
 8. The flexible display apparatus of claim 7, furthercomprising a barrier film between the third film and the device/wiringlayer.
 9. The flexible display apparatus of claim 1, further comprisinga second film on the fourth film.
 10. A method of manufacturing aflexible display apparatus, the method comprising: forming a third filmon a supporting substrate; forming an emission display unit on the thirdfilm; forming a fourth film on the emission display unit; forming asecond film having a second rigidity over the fourth film; separatingthe supporting substrate from the third film; and forming a first filmon a surface of the third film opposite to another surface of the thirdfilm on which the emission display unit is formed, wherein the firstfilm has a first rigidity greater than the second rigidity and comprisesa second surface adjacent to the third film, and a first surface that isopposite to the second surface and has a first opening or groove,wherein the emission display unit comprises a pixel electrode on thethird film, an organic emission layer on the pixel electrode, and anopposite electrode on the organic emission layer, wherein the fourthfilm is on the opposite electrode, wherein a width of the first openingor groove is at least two times greater than a thickness of the firstfilm, and wherein an adhesion layer is further formed between the firstfilm and the third film, and a surface of the adhesion layer is exposedby the first opening or groove.
 11. The method of claim 10, wherein thefirst film is divided by the first opening or groove into a first regionand a second region, and a portion of the third film is exposed at aregion corresponding to the first opening or groove.
 12. The method ofclaim 11, wherein the fourth film is formed on the organic emissionlayer.
 13. The method of claim 12, wherein the fourth film is formed asa multi-layer.
 14. The method of claim 13, wherein the multi-layercomprises at least one inorganic film.
 15. The method of claim 11,wherein the first opening or groove is positioned at a bending portionof the second film, the third film, and the fourth film.
 16. The methodof claim 15, wherein a neutral portion in which a tensile stress and acompressive stress are not incurred by a force when the force is appliedto the bending portion exists between the first film and the secondfilm.
 17. The method of claim 15, wherein the second film, the thirdfilm and the fourth film are bent by at least 90 degrees at the bendingportion.
 18. The method of claim 17, wherein a neutral portion in whicha tensile stress and a compressive stress are not incurred by a forcewhen the force is applied to the bending portion exists between thefirst film and the second film.
 19. A flexible display apparatuscomprising: a first film including a first region and a second regionseparated from the first region by a first opening or groove of thefirst film, the first opening or groove being disposed in the firstfilm; a third film over the first film; a fourth film over the thirdfilm; an emission display unit between the third film and the fourthfilm; and an adhesion layer disposed between the first film and thethird film; wherein a width of the first opening or groove of the firstfilm is at least two times greater than a thickness of the first film, asurface of the adhesion layer between the third film and the first filmis exposed by the first opening or groove, and a depth of the firstopening or groove is equal to the thickness of the first film.
 20. Aflexible display apparatus comprising: a first film including a firstregion and a second region separated from the first region by a firstopening or groove of the first film, the first opening or groove beingdisposed in the first film; a third film over the first film; a fourthfilm over the third film; an emission display unit between the thirdfilm and the fourth film; and an adhesion layer between the first filmand the third film; wherein a width of the first opening or groove ofthe first film is at least two times greater than a thickness of thefirst film, and a surface of the third film between the emission displayunit and the adhesion layer is exposed by the first opening or groove.21. The flexible display apparatus of claim 20, wherein the third filmcomprises a plastic material.
 22. The flexible display apparatus ofclaim 20, wherein the fourth film comprises a multi-layer.
 23. Theflexible display apparatus of claim 22, wherein the multi-layercomprises at least one inorganic film.
 24. The flexible displayapparatus of claim 20, wherein the fourth film is configured toencapsulate the emission display unit.
 25. The flexible displayapparatus of claim 20, further comprising a barrier film between thethird film and the emission display unit.
 26. The flexible displayapparatus of claim 20, further comprising a device/wiring layer betweenthe third film and the emission display unit.
 27. The flexible displayapparatus of claim 26, further comprising a barrier film between thethird film and the device/wiring layer.
 28. The flexible displayapparatus of claim 20, further comprising a second film on the fourthfilm.
 29. A flexible display apparatus comprising: a first filmincluding a first region and a second region separated from the firstregion by a first opening or groove of the first film, the first openingor groove being disposed in the first film; a third film over the firstfilm; a fourth film over the third film; an emission display unitbetween the third film and the fourth film; and an adhesion layerdisposed between the first film and the third film, wherein a width ofthe first opening or groove of the first film is at least two timesgreater than a thickness of the first film, a surface of the third filmbetween the emission display unit and the adhesion layer is exposed bythe first opening or groove, and a depth of the first opening or grooveis equal to the thickness of the first film.
 30. A method ofmanufacturing a flexible display apparatus, the method comprising:forming a third film on a supporting substrate; forming an emissiondisplay unit on the third film; forming a fourth film on the emissiondisplay unit; forming a second film having a second rigidity over thefourth film; separating the supporting substrate from the third film;and forming a first film on a surface of the third film opposite toanother surface of the third film on which the emission display unit isformed, wherein the first film has a first rigidity greater than thesecond rigidity and comprises a first opening or groove, wherein theemission display unit comprises a pixel electrode on the third film, anorganic emission layer on the pixel electrode, and an opposite electrodeon the organic emission layer, wherein the fourth film is on theopposite electrode, wherein a width of the first opening or groove is atleast two times greater than a thickness of the first film, and whereinan adhesion layer is further formed between the first film and the thirdfilm, and a surface of the third film between the fourth film and theadhesion layer is exposed by the first opening or groove.